I've been playing a lot of BF3 and I've noticed I'm starting to get a bit of lag on capsian border, the settings are set to auto and I tend to get some FPS lag dropping into slightly stuttery range every now and again, I'v dropped it to medium with no increase in FPS it seems.

Now, I can pick up a Phenom II X6 1045T cheap and turn that 4GB into 8GB or 16GB RAM fairly easily and get x64 Win 7, would that help fix the issue or should I focus my money on a better graphics card, like a 6970?

I have a 1055T 2.81GHz, 8GB of RAM and 2 - 6870's and I ran a monitor last night while playing BF3. I didn't have a core under 60% utilization and both GPU's stayed between 60-90%. This game appears to use everything you can throw at it.